<?php // $Id: editlib.php,v 1.54.2.5 2008/04/17 08:28:24 moodler Exp $
/**
 * Functions used by edit.php to edit quizzes
 *
 * @author Martin Dougiamas and many others. This has recently been extensively
 *		 rewritten by members of the Serving Mathematics project
 *		 {@link http://maths.york.ac.uk/serving_maths}
 * @license http://www.gnu.org/copyleft/gpl.html GNU Public License
 * @package quiz
 */

require_once("locallib.php");

/**
* Delete a question from a quiz
*
* Deletes a question or a pagebreak from a quiz by updating $quiz
* as well as the quiz, quiz_question_instances
* @return boolean		 false if the question was not in the quiz
* @param int $id		  The id of the question to be deleted
* @param object $quiz  The extended quiz object as used by edit.php
*						 This is updated by this function
*/
function quiz_delete_quiz_question($id, &$quiz) {
	// TODO: For the sake of safety check that this question can be deleted
	// safely, i.e., that it is not already in use.
	$questions = explode(",", $quiz->questions);

	// only do something if this question exists
	if (!isset($questions[$id])) {
		return false;
	}

	$question = $questions[$id];
	unset($questions[$id]);
	// If we deleted the question at the top and it was followed by
	// a page break then delete page break as well
	if ($id == 0 && count($questions) > 1 && $questions[1] == 0) {
		unset($questions[1]);
	}
	$quiz->questions = implode(",", $questions);
	// Avoid duplicate page breaks
	$quiz->questions = str_replace(',0,0', ',0', $quiz->questions);
	// save new questionlist in database
	if (!set_field('quiz', 'questions', $quiz->questions, 'id', $quiz->instance)) {
		error('Could not save question list');
	}
	delete_records('quiz_question_instances', 'quiz', $quiz->instance, 'question', $question);
	return true;
}


/**
* Add a question to a quiz
*
* Adds a question to a quiz by updating $quiz as well as the
* quiz and quiz_question_instances tables. It also adds a page break
* if required.
* @return boolean		 false if the question was already in the quiz
* @param int $id		  The id of the question to be added
* @param object $quiz  The extended quiz object as used by edit.php
*						 This is updated by this function
*/
function quiz_add_quiz_question($id, &$quiz) {
	$questions = explode(",", $quiz->questions);

	if (in_array($id, $questions)) {
		return false;
	}

	// remove ending page break if it is not needed
	if ($breaks = array_keys($questions, 0)) {
		// determine location of the last two page breaks
		$end = end($breaks);
		$last = prev($breaks);
		$last = $last ? $last : -1;
		if (!$quiz->questionsperpage or (($end - $last -1) < $quiz->questionsperpage)) {
			array_pop($questions);
		}
	}
	// add question
	$questions[] = $id;
	// add ending page break
	$questions[] = 0;

	// Save new questionslist in database
	$quiz->questions = implode(",", $questions);
	if (!set_field('quiz', 'questions', $quiz->questions, 'id', $quiz->id)) {
		error('Could not save question list');
	}

	// update question grades
	$questionrecord = get_record("question", "id", $id);
	$quiz->grades[$id]
			= $questionrecord->defaultgrade;
	quiz_update_question_instance($quiz->grades[$id], $id, $quiz->instance);

	return true;
}

/**
* Save changes to question instance
*
* Saves changes to the question grades in the quiz_question_instances table.
* It does not update 'sumgrades' in the quiz table.
* @return boolean		 Indicates success or failure.
* @param integer grade	The maximal grade for the question
* @param integer $questionid  The id of the question
* @param integer $quizid  The id of the quiz to update / add the instances for.
*/
function quiz_update_question_instance($grade, $questionid, $quizid) {
	if ($instance = get_record("quiz_question_instances", "quiz", $quizid, 'question', $questionid)) {
		$instance->grade = $grade;
		return update_record('quiz_question_instances', $instance);
	} else {
		unset($instance);
		$instance->quiz = $quizid;
		$instance->question = $questionid;
		$instance->grade = $grade;
		return insert_record("quiz_question_instances", $instance);
	}
}

/**
* Prints a list of quiz questions in a small layout form with knobs
*
* @return int sum of maximum grades
* @param object $quiz This is not the standard quiz object used elsewhere but
*	 it contains the quiz layout in $quiz->questions and the grades in
*	 $quiz->grades
* @param boolean $allowdelete Indicates whether the delete icons should be displayed
* @param boolean $showbreaks  Indicates whether the page breaks should be displayed
* @param boolean $showbreaks  Indicates whether the reorder tool should be displayed
*/
function quiz_print_question_list($quiz, $pageurl, $allowdelete=true, $showbreaks=true, $reordertool=false) {
	global $USER, $CFG, $QTYPES;

	$strorder = get_string("order");
	$strquestionname = get_string("questionname", "quiz");
	$strgrade = get_string("grade");
	$strremove = get_string('remove', 'quiz');
	$stredit = get_string("edit");
	$strview = get_string("view");
	$straction = get_string("action");
	$strmoveup = get_string("moveup");
	$strmovedown = get_string("movedown");
	$strsavegrades = get_string("savegrades", "quiz");
	$strtype = get_string("type", "quiz");
	$strpreview = get_string("preview", "quiz");

	if (!$quiz->questions) {
		echo "<p class=\"quizquestionlistcontrols\">";
		print_string("noquestions", "quiz");
		echo "</p>";
		return 0;
	}

	if (!$questions = get_records_sql("SELECT q.*,c.contextid
							  FROM {$CFG->prefix}question q,
								   {$CFG->prefix}question_categories c
							 WHERE q.id in ($quiz->questions)
							   AND q.category = c.id")) {
		echo "<p class=\"quizquestionlistcontrols\">";
		print_string("noquestions", "quiz");
		echo "</p>";
		return 0;
	}

	$count = 0;
	$qno = 1;
	$sumgrade = 0;
	$order = explode(',', $quiz->questions);
	$lastindex = count($order)-1;
	// If the list does not end with a pagebreak then add it on.
	if ($order[$lastindex] != 0) {
		$order[] = 0;
		$lastindex++;
	}
	echo "<form method=\"post\" action=\"edit.php\">";
	echo '<fieldset class="invisiblefieldset" style="display: block;">';
	echo "<input type=\"hidden\" name=\"sesskey\" value=\"$USER->sesskey\" />";
	echo $pageurl->hidden_params_out();

	echo "<table style=\"width:100%;\">\n";
	echo "<tr><th colspan=\"3\" style=\"white-space:nowrap;\" class=\"header\" scope=\"col\">$strorder</th>";
	echo "<th class=\"header\" scope=\"col\">#</th>";
	echo "<th align=\"left\" style=\"white-space:nowrap;\" class=\"header\" scope=\"col\">$strquestionname</th>";
	echo "<th style=\"white-space:nowrap;\" class=\"header\" scope=\"col\">$strtype</th>";
	echo "<th style=\"white-space:nowrap;\" class=\"header\" scope=\"col\">$strgrade</th>";
	echo "<th align=\"center\" style=\"white-space:nowrap;\" class=\"header\" scope=\"col\">$straction</th>";
	echo "</tr>\n";

	// for RTL languages: switch right and left arrows /****/
	if (right_to_left()) { 
		$movearrow = 'moveleft.gif'; 
	} else { 
		$movearrow = 'removeright.gif'; 
	} 

	foreach ($order as $i => $qnum) {

		if ($qnum and empty($questions[$qnum])) {
			continue;
		}

		// If the questiontype is missing change the question type
		if ($qnum and !array_key_exists($questions[$qnum]->qtype, $QTYPES)) {
			$questions[$qnum]->qtype = 'missingtype';
		}

		// Show the re-ordering field if the tool is turned on.
		// But don't show it in front of pagebreaks if they are hidden.
		if ($reordertool) {
			if ($qnum or $showbreaks) {
				echo '<tr><td><input type="text" name="o'.$i.'" size="2" value="'.(10*$count+10).'" /></td>';
			} else {
				echo '<tr><td><input type="hidden" name="o'.$i.'" size="2" value="'.(10*$count+10).'" /></td>';
			}
		} else {
			echo '<tr><td></td>';
		}
		if ($qnum == 0) { // This is a page break
			if ($showbreaks) {
				echo '<td colspan ="3">&nbsp;</td>';
				echo '<td><table style="width:100%; line-height:11px; font-size:9px; margin: -5px -5px;"><tr>';
				echo '<td><hr /></td>';
				echo '<td style="width:50px;">Page break</td>';
				echo '<td><hr /></td>';
				echo '<td style="width:45px;">';
				if ($count > 1) {
					echo "<a title=\"$strmoveup\" href=\"".$pageurl->out_action(array('up'=>$count))."\"><img
						 src=\"$CFG->pixpath/t/up.gif\" class=\"iconsmall\" alt=\"$strmoveup\" /></a>";
				}
				echo '&nbsp;';
				if ($count < $lastindex) {
					echo "<a title=\"$strmovedown\" href=\"".$pageurl->out_action(array('down'=>$count))."\"><img
						 src=\"$CFG->pixpath/t/down.gif\" class=\"iconsmall\" alt=\"$strmovedown\" /></a>";

					echo "<a title=\"$strremove\" href=\"".$pageurl->out_action(array('delete'=>$count))."\">
						  <img src=\"$CFG->pixpath/t/delete.gif\" class=\"iconsmall\" alt=\"$strremove\" /></a>";
				}
				echo '</td></tr></table></td>';
				echo '<td colspan="2">&nbsp;</td>';
			}
			$count++;
			// missing </tr> here, if loop is broken, need to close the </tr>
			echo "</tr>";
			continue;
		}
		$question = $questions[$qnum];

		echo "<td>";
		if ($count != 0) {
			echo "<a title=\"$strmoveup\" href=\"".$pageurl->out_action(array('up'=>$count))."\"><img
				 src=\"$CFG->pixpath/t/up.gif\" class=\"iconsmall\" alt=\"$strmoveup\" /></a>";
		}
		echo "</td>";
		echo "<td>";
		if ($count < $lastindex-1) {
			echo "<a title=\"$strmovedown\" href=\"".$pageurl->out_action(array('down'=>$count))."\"><img
				 src=\"$CFG->pixpath/t/down.gif\" class=\"iconsmall\" alt=\"$strmovedown\" /></a>";
		}
		echo "</td>";

		if (!$quiz->shufflequestions) {
			// Print and increment question number
			echo '<td>'.($question->length ? $qno : '&nbsp;').'</td>';
			$qno += $question->length;
		} else {
			echo '<td>&nbsp;</td>';
		}

		echo '<td>' . format_string($question->name) . '</td>';
		echo "<td align=\"center\">";
		print_question_icon($question);
		echo "</td>";
		echo '<td align="left">';
		if ($question->qtype == 'description') {
			echo "<input type=\"hidden\" name=\"q$qnum\" value=\"0\" /> \n";
		} else {
			echo '<input type="text" name="q'.$qnum.'" size="2" value="'.$quiz->grades[$qnum].
			 '" tabindex="'.($lastindex+$qno).'" />';
		}
		echo '</td><td align="center">';

		if (($question->qtype != 'random')){
			echo quiz_question_preview_button($quiz, $question);
		}
		$returnurl = $pageurl->out();
		$questionparams = array('returnurl' => $returnurl, 'cmid'=>$quiz->cmid, 'id' => $question->id);
		$questionurl = new moodle_url("$CFG->wwwroot/question/question.php", $questionparams);
		if (question_has_capability_on($question, 'edit', $question->category) || question_has_capability_on($question, 'move', $question->category)) {
			echo "<a title=\"$stredit\" href=\"".$questionurl->out()."\">
					<img src=\"$CFG->pixpath/t/edit.gif\" class=\"iconsmall\" alt=\"$stredit\" /></a>";
		} elseif (question_has_capability_on($question, 'view', $question->category)){
			echo "<a title=\"$strview\" href=\"".$questionurl->out(false, array('id'=>$question->id))."\"><img
					src=\"$CFG->pixpath/i/info.gif\" alt=\"$strview\" /></a>&nbsp;";
		}
		if ($allowdelete && question_has_capability_on($question, 'use', $question->category)) { // remove from quiz, not question delete.
			echo "<a title=\"$strremove\" href=\"".$pageurl->out_action(array('delete'=>$count))."\">
					<img src=\"$CFG->pixpath/t/$movearrow\" class=\"iconsmall\" alt=\"$strremove\" /></a>";
		}

		echo "</td></tr>";
		$count++;
		$sumgrade += $quiz->grades[$qnum];
	}

	echo "<tr><td colspan=\"6\" align=\"right\">\n";
	print_string('total');
	echo ": </td>";
	echo "<td align=\"left\">\n";
	echo "<strong>$sumgrade</strong>";
	echo "</td><td>&nbsp;\n</td></tr>\n";

	echo "<tr><td colspan=\"6\" align=\"right\">\n";
	print_string('maximumgrade');
	echo ": </td>";
	echo "<td align=\"left\">\n";
	echo '<input type="text" name="maxgrade" size="2" tabindex="'.($qno+1)
	 .'" value="'.$quiz->grade.'" />';
	echo '</td><td align="left">';
	helpbutton("maxgrade", get_string("maximumgrade"), "quiz");
	echo "</td></tr></table>\n";

	echo '<div class="quizquestionlistcontrols"><input type="submit" value="'.get_string('savechanges').'" />';
	echo '<input type="hidden" name="savechanges" value="save" /></div>';

	echo '</fieldset>';
	echo "</form>\n";

/// Form to choose to show pagebreaks and to repaginate quiz
	echo '<form method="post" action="edit.php" id="showbreaks">';
	echo '<fieldset class="invisiblefieldset">';
	echo $pageurl->hidden_params_out(array('showbreaks', 'reordertool'));
	echo '<input type="hidden" name="sesskey" value="'.$USER->sesskey.'" />';
	echo '<input type="hidden" name="showbreaks" value="0" />';
	echo '<input type="checkbox" name="showbreaks" value="1"';
	if ($showbreaks) {
		echo ' checked="checked"';
	}
	echo ' onclick="form.submit(); return true;" />';
	print_string('showbreaks', 'quiz');

	if ($showbreaks) {
		$perpage= array();
		for ($i=0; $i<=50; ++$i) {
			$perpage[$i] = $i;
		}
		$perpage[0] = get_string('allinone', 'quiz');
		echo '<br />&nbsp;&nbsp;';
		print_string('repaginate', 'quiz',
		 choose_from_menu($perpage, 'questionsperpage', $quiz->questionsperpage, '', '', '', true));
	}

	echo '<br /><input type="hidden" name="reordertool" value="0" />';
	echo '<input type="checkbox" name="reordertool" value="1"';
	if ($reordertool) {
		echo ' checked="checked"';
	}
	echo ' onclick="form.submit(); return true;" />';
	print_string('reordertool', 'quiz');
	echo ' ';
	helpbutton('reorderingtool', get_string('reordertool', 'quiz'), 'quiz');
	
	echo '<div class="quizquestionlistcontrols"><input type="submit" name="repaginate" value="'. get_string('go') .'" /></div>';
	echo '</fieldset>';
	echo '</form>';

	return $sumgrade;
}

?>
